The Pentagon said a Russian fighter jet made multiple close-range passes near an American navy destroyer. The warship was deployed in the Black Sea as Russian military suspects NATO’s systematic build-up of naval forces in the region.

"This provocative and unprofessional Russian action is
inconsistent with their national protocols and previous
agreements on the professional interaction between our
militaries," said Colonel Steve Warren, a Pentagon
spokesman.

"I have difficulty believing that two Russian pilots on their
own would choose to take such an action."

Pentagon defined the jet as a Russian Su-24 aircraft, or Fencer,
which made 12 passes at low altitude near the USS Donald Cook
that, at the time, was conducting a patrol in international
waters in the western Black Sea, Reuters reported.

Earlier, a military official told AP that on April, 12, a Russian
aircraft flew repeatedly within 1,000 yards of the USS Donald
Cook at about 500 feet above sea level for over 90 minutes.

According to the official, the destroyer’s crew made several
attempts to radio the Russian warplane requesting the reason for
the manoeuvre. They then reportedly issued warnings to remain at
a safe distance, however, there was no response from the Russian
pilot.

Pentagon confirmed the fighter jet was not armed with any aerial
bombs.

A second jet was observed was observed slightly further from the
ship.

"The Donald Cook is more than capable of defending herself
against two Su-24s," said Warren.

The US Defense Department claimed the ship’s mission was “to
reassure NATO allies and Black Sea partners” following the
events in Ukraine.

On Monday, the USS Donald Cook entered waters of Romania.

‘NATO violates Montreux Convention’

Last week the Russian military considered the USS Donald Cook
manoeuvre part of a systematic build-up of naval forces.

“What we are seeing is that for the first time since 2008,
NATO is creating a naval battle group outside Russian
borders,” a Russian military source told Interfax news
agency.

On April, 3, Foreign Minister Sergey Lavrov accused NATO of
violating the Montreux Convention, which regulates the number
ships that can enter the Black Sea, saying that “US warships
have extended their deployment beyond the set terms a couple of
times lately.”

According to the treaty, warships from non-Black Sea states can
only stay in the basin for up to 21 days consecutively. USS
Taylor spent 11 more than that in the region in February and
March.

Russia’s Foreign Ministry expressed “bemusement” over
the move.

“Turkey [which administers the treaty] did not inform us
about the overstay. We have expressed our concern to the Turkish
and US side in a verbal note,” said a statement on the
ministry website.